Managed C++/CLI

TabascoSauce wrote:

The continue button overwrites the previous values for "1num" 2num and "ans" with 4, 5, and 9

ref class QA{
public:
	QA(int f, int s, int input)
		: firstNumber(f)
		, secondNumber(s)
		, userInput(input)

	{}

	property int FirstNumber{
		int get(){
			return firstNumber;
		}
	}

	property int SecondNumber{
		int get(){
			return secondNumber;
		}
	}

	property int UserInput{
		int get(){
			return userInput;
		}
	}

private:
	int firstNumber, secondNumber, userInput;
};

using namespace System::Collections::Generic;
List<QA^>^ qaList = gcnew List<QA^>();
// start your loop
qaList->Add(gcnew QA(FirstRandomNumber,SecondRandomNumber,UserInput));
// your loop ends here
// you will get all the values here if you iterate qaList.

TabascoSauce wrote:

Form^ DoMath = gcnew Form();
DoMath->Show();

and that opens up a new form when I hit the button on my first form

Lavake wrote:

But this doesn't work.

Lavake wrote:

For example, a function (outside the form header file) should be able to update a textfield in the form, during its execution. What would be the best way to do this in C++?

MainForm^ mainform = gcnew MainForm();
Application::Run(mainform);
mainform->addUpdates("test");

Lavake wrote:

MainForm^ mainform = gcnew MainForm();
Application::Run(mainform);
mainform->addUpdates("test");

roshihans wrote:

But then another problem comes out. The instance declared in Form Child.cpp is not the same instance as the previous FormMain

roshihans wrote:

So, what is the correct way to solve this problem?

roshihans wrote:

AddTextChangeCallback(textBox1->Text );

System::Void btnAdd_Click(System::Object^ sender, System::EventArgs^ e)
{
    if(AddTextChangeCallback != nullptr)
        AddTextChangeCallback(textBox1->Text ); // Safe to call it now
}

roshihans wrote:

// declaring delegate, and get "error C2143: syntax error : missing ';' before '^' "
// the compiler seems doesn't recognize this

public ref class FormChild : System::Windows::Forms::Form
{
   public:
        delegate void AddTextChangeDelegate();
	AddTextChangeDelegate^ AddTextChangeCallback;
	
        ...........

};

N a v a n e e t h wrote:

Because you are instantiating a new instance in the child form. You need to pass the main form's instance to child form (through constructor injection or some setter methods).

roshihans wrote:

constructor injection?

Form2(Form1^ form1) // First form's object is injected through constructor
{
    // keep the form1 object for future use
}

N a v a n e e t h wrote:

By constructor injection, I meant to pass the first form's object to second form via constructor. Something like

Form2(Form1^ form1) // First form's object is injected through constructor
{
    // keep the form1 object for future use
}

roshihans wrote:

But Form1 already include Form2.h (in my case Form1 act as a "parent" form, and instantiate Form2). So I think I can't declare Form2 (Form1^ form1) and keep the form1 object, like you have mentioned above

public ref class PForm : public System::Windows::Forms::Form{
public:
    void UpdateText(String^ str) // used to update the text box text. This will be called from CForm.
    {
	textBox1->Text = str;
    }

    // your rest of code
};

ref class PForm; // forward declaring PForm

public ref class CForm : public System::Windows::Forms::Form{
public:
    CForm(PForm^ pf) // injecting dependency through constructor
    {
	InitializeComponent();
	pForm = pf;
    }

private: 
    System::Void textBox1_TextChanged(System::Object^, System::EventArgs^);
    PForm^ pForm; // Parent form's object used to update the control
};

#include "CForm.h"
#include "PForm.h"

System::Void CForm::textBox1_TextChanged(System::Object ^sender, System::EventArgs ^e){
	if(pForm != nullptr)
		pForm->UpdateText(textBox1->Text);
}

CForm^ cForm = gcnew CForm(this);
cForm->Show();

private: System::Void northT_Click(System::Object^  sender, System::EventArgs^  e) 
		 {
			 //Variables
			 double nTotalIn = 0.0;
			 double nTotalFi = 0.0;
			 double n1 = 0.0;
			 double n2 = 0.0;
			 double n3 = 0.0;

			 do
			 {
				 nTotalIn = Convert::ToDouble(northT->Text);
				 n1 = Convert::ToDouble(north1->Text);
				 n2 = Convert::ToDouble(north2->Text);
				 n3 = Convert::ToDouble(north3->Text);
				 nTotalFi = n1 + n2 + n3;
				 northT->Text = nTotalFi.ToString();
			 } while(nTotalFi != nTotalIn);
		 }

System::Int64 limit1 = 100;
System::Int64 limit2 = 25;
System::Int64 diff = limit1 - limit2;

System::Int64^ limit1 = gcnew System::Int64(100);
System::Int64^ limit2 = gcnew System::Int64(25);
System::Int64^ diff = gcnew System::Int64(*limit1 - *limit2);

Mark Salsbery
Microsoft MVP - Visual C++